Oh, I don't use C for every command-line utility. If it's something IO-bound like parsing a webpage and downloading a bunch of files linked from it, I write it in Python. The convenience of modules like argparse and requests is very hard to beat, and it would take me a lot longer to do it in C.

I reach for C when performance matters, for example when processing multi-GB files or looking for perceptual hashes that are similar. It can be a difference between minutes and hours of running time.